Data Sheet

380. NOT Gate Applications
Build the circuit shown on the left. Note that the lamp (76) is on when
the press switch (61) is off and the lamp (76) is off when the press
switch (61) is on. You might have a circuit like this in your car, where
the light in your car stays on while the door is open, but when you close
the door, it’s like pressing the press switch (61) and the light goes out.
381. NAND Gate
Build the circuit from project #380 but add
the switch (62) in series with the press
switch (61). Note that the lamp (76) is
always on unless both the switch (62) and
the press switch (61) are on. This describes
a Not-AND-Gate or NAND Gate. The symbol
and logic diagram for the NAND gate are
shown to the right. A circle at the right end
of the AND gate symbol represents a “NOT”
function, so you can think of the NAND gate
as an AND gate followed by a NOT gate.
382. NOR Gate
Build the circuit from project #380 but add
the switch (62) in parallel with the press
switch (61). Note that the lamp (76) is ON
unless either the switch (62) or the press
switch (61) are on. This describes a Not-
OR-Gate or NOR-Gate. The symbol and logic
diagram for the NOR gate are shown to the
right. A circle at the right end of the OR gate
symbol represents a “NOT” function, so you
can think of the NOR gate as an OR gate
followed by a NOT gate.
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Inputs Output
A B C
OFF OFF ON
OFF ON ON
ON OFF ON
ON ON OFF
NAND Gate
Inputs Output
A B C
OFF OFF ON
OFF ON OFF
ON OFF OFF
ON ON OFF
NOR Gate